This disclosure relates to a flying vehicle and more specifically to a hovering vehicle that includes a control system to automatically control the height of the vehicle relative to a surface or another object.
The control method is basically related to the distance measurement. Some flying toys handle it with ultrasonic sensor. A MCU connects to this sensor; it starts the timer while emitting a pulse train from the sensor. MCU then measures the time elapsed of reflected signal from the ground surface. As the speed of sound is known, the distance traveled can be calculated. The limitation of this application is that this sensor is comparatively large and heavy for putting into a small flying toy with size less than 250 mm in length.
Alternatively, precise pressure sensor can be used to level the absolute altitude for both indoor and outdoor flying toys but the solution cost is too high to be applied in toys market and the data is drifted from time to time.